Screen apparatus for vibratory separator

ABSTRACT

A screen is disclosed which, in certain aspects, has screening material between opposed frame sides and one or more lower strips beneath the screen. In one aspect these strips are only inteconnected via their ends and not along their lengths. In certain aspects, a plurality of lower strips are bonded to the screen and extend across the screen from one frame side to the other. In one aspect one or more of the strips has one, two, or more humps or ridges corresponding to one or more corrugations in a corrugated perforated plate and/or corrugated screen assembly which is on the plate or, with no plate present, on the strips. In another aspect instead of the strips a solid corrugated perforated plate is used. In one aspect openings or perforations through the plate are triangular. In one aspect the screen is undulating screening material and lower portions of the screening material are bonded to a plate or to strips. Optionally screen mounting hooks or frame edges or screen edges may be used with such screens. A screening apparatus or shale shaker is disclosed which uses such plates and screens.

RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 08/786,515filed Jan. 21, 1997 which is a continuation in part of the followingco-owned applications and patents: U.S. Ser. No. 29/048,575 filed Jan.4, 1996, now U.S. Pat. No. D 377,636, which is a continuation of U.S.Ser. No. 29/014,571, now U.S. Pat. No. D 366,040 issued on Jan. 9, 1996which is a continuation-in-part of U.S. applications: Ser. No.07/956,123 filed Apr. 30, 1993, now U.S. Pat. No. 5,385,669 issued onJan. 31, 1995; and Ser. No. 08/105,696 filed Aug. 12, 1993, now U.S.Pat. No. 5,392,925 issued on Feb. 28, 1995; U.S. Ser. No. 08/504,495filed Jul. 20, 1995 entitled "Shale Shaker Screen" issued as U.S. Pat.No. 5,598,930 on Feb. 4, 1997; U.S. Ser. No. 08/598,566 filed Feb. 12,1996 now abandoned entitled "Screen For Vibrating Separator" which is acontinuation-in-part of U.S. Ser. No. 08/220/101 filed Mar. 30, 1994 nowU.S. Pat. No. 5,490,598 issued Feb. 13, 1996. All of these relatedapplications and patents are incorporated herein in their entirety forall purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to vibratory screens, to filteringscreens, to such screens that are generally flat or that are not flat,to devices with such screens, and to shale shakers with such screens,and to shakers for separating particles.

2. Description of Related Art

The need for solids control in drilling mud used in hydrocarbon welldrilling is well known in the prior art. Drilling mud, typically amixture of clay and water and various additives, is pumped down througha hollow drill string (pipe, drill collar, bit, etc.) into a well beingdrilled and exits through holes in a drillbit. The mud picks up cuttings(rock) and other solids from the well and carries them upwardly awayfrom the bit and out of the well in a space between the well walls andthe drill string. At the top of the well, the solids-laden mud isdischarged over a shale shaker, a device which typically has a series ofscreens arranged in tiered or flat disposition with respect to eachother. The prior art discloses a wide variety of vibrating screens,devices which use them, shale shakers, and screens for shale shakers.The screens catch and remove solids from the mud as the mud passesthrough them. If drilled solids are not removed from the mud used duringthe drilling operation, recirculation of the drilled solids can createweight, viscosity, and gel problems in the mud, as well as increasingwear on mud pumps and other mechanical equipment used for drilling.

In some shale shakers a fine screen cloth is used with the vibratingscreen. The screen may have two or more overlying layers of screencloth. The prior art discloses that the layers may be bonded together;and that a support, supports, or a perforated or apertured plate may beused beneath the screen or screens. The frame of the vibrating screen isresiliently suspended or mounted upon a support and is caused to vibrateby a vibrating mechanism, e.g. an unbalanced weight on a rotating shaftconnected to the frame. Each screen may be vibrated by vibratoryequipment to create a flow of trapped solids on top surfaces of thescreen for removal and disposal of solids. The fineness or coarseness ofthe mesh of a screen may vary depending upon mud flow rate and the sizeof the solids to be removed.

Many screens used with shale shakers are flat or nearly flat (i.e.substantially two-dimensional). Other screens, due to corrugated,depressed, or raised surfaces are three-dimensional. U.S. Pat. Nos.5,417,793; 5,417,858; and 5,417,859 disclose non-flat screens for usewith shale shakers. These screens have a lower planar apertured platewith a multiplicity of spaced-apart apertures or openings therethrough.Undersides of troughs of undulating screening material are bonded to theapertured plate. Such screens present a variety of problems,deficiencies, and disadvantages, including: decreased flow area due toarea occluded by solid parts of the apertured plate; necessity to eitherpurchase relatively expensive apertured plate or provide for in-houseperforating of a solid plate; plate weight increases wear on parts suchas rubber screen supports or cushions and can inhibit requiredvibration; large plate surface area requires relatively large amount ofbonding means for bonding screens to the plate; and a finished screenwhich is relatively heavy increases handling problems, hazards, and costof shipping.

Vibrating screens have been employed for many years to separateparticles in a wide array of industrial applications. One commonapplication of vibrating screens is in drilling operations to separateparticles suspended in drilling fluids. The screens are generally flatand are mounted generally horizontally on a vibrating mechanism orshaker that imparts either a rapidly reciprocating linear, elliptical orcircular motion to the screen. Material from which particles are to beseparated is poured onto a back end of the vibrating screen, usuallyfrom a pan mounted above the screen. The material generally flows towardthe front end of the screen. Large particles are unable to move throughthe screen remaining on top of the screen and moving toward the front ofthe screen where they are collected. The smaller particles and fluidflows through the screen and collects in a pan beneath the screen.

A vibrating screen may be formed from one or more layers of wire mesh.Wire mesh is generally described with reference to the diameter of thewires from which it is woven, the number wires per unit length (called amesh count) and the shape or size of the openings between wires. Wiremesh comes in various grades. "Market" grade mesh generally has wires ofrelative large diameter. "Mill" grade has comparatively smaller diameterwires and "bolting cloth" has the smallest diameter wire. The type ofmesh chosen depends on the application. Smaller diameter wires have lesssurface and thus less drag, resulting in greater flow rates. Smallerdiameter wires also result, for a given opening size, in a largerpercentage of open area over the total area of the screen, thus allowinggreater flow rates and increased capacity. However, screens of boltingcloth tears more easily than market or mill grade screens, especiallywhen used in harsh conditions such as drilling and mining operations.The smaller diameter wires tend to have less tensile strength and breakmore easily, and the finer mesh also tends not to retain its shape well.

Most meshes suffer from what is termed as "near sized particle blinding.During vibration, wires separate enough to allow particles ofsubstantially the same size or slightly larger than the openings to fallbetween the wires and become ledged, thus "blinding" the openings of thescreen and reducing capacity of the screen. If a particle becomes lodgedwhen the wires are at a maximum distance apart, it is almost impossibleto dislodge the particle. Sometimes, however, wires will subsequentlyseparate further to release the lodged particle. Unfortunately, somewire mesh, especially bolting cloth, is tensioned. Tensioning restrictsmovement of the wires. Restricting movement assists in holding the shapeof the wire mesh, keeping the size of the openings consistent to createa more consistent or finer "cutting point" and reducing abrasion fromwires rubbing against each other. However, restricted movement of thewires reduces the probability that, once a near sized particle becomesstuck, the wires will subsequently separate to allow the particle topass. Use of smaller diameter wires, with smaller profiles, helps toreduce blinding. With a smaller diameter wire, a particle is less likelyto become lodged midway through the opening.

Multiple layers of mesh may be used to alleviate blinding. U.S. Pat. No.4,033,865, describes layering two meshes in a manner that results in atleast one wire of the lower of the two meshes bisecting each opening inthe upper mesh. The openings in each mesh are at least twice as wide asthe diameters of the wires and the lower mesh has openings the same sizeas or slightly larger than the openings in the upper mesh. The lowermesh, when held tightly against the upper mesh, prevents particles frommigrating far enough into an opening in the upper mesh to be trapped.Some relative movement of the layers also helps to dislodge particlescaught in the upper layer. The two-layer arrangement has the furtherbenefit of a finer "cutting point," allowing smaller particles to beseparated out. A third "backing" layer of relatively coarse, mill grademesh is often used to carry most of the load on the screen and toincrease the tensile strength of the screen.

Another problem faced in most applications is the tearing of the screen.The problem can be especially acute in heavy duty applications such asdrilling and mining. A torn screen must be replaced or repaired. Tofacilitate repair, the screen layers are bonded to a rigid or semi-rigidsupport panel that has a pattern of large openings, forming on thescreen a plurality of small cells of wire mesh. When a tear occurs inthe screen, the mesh remaining within the cell in which the tearoccurred is cut out and the cell is plugged. The capacity of the screenis diminished but its life is extended. Typically, several cells of ascreen can be repaired before its capacity drops far enough to requirereplacement. Unfortunately, bonding the screen to the support panelfurther restricts relative movement of the layers and the wires in eachmesh layer, thus compounding the problem of blinding.

Blinding and tearing of the screens reduce the capacity of the screencontinually through its useful life. Although capacity can be increasedby increasing the total area the screens, the size of the screen islimited in most applications, such as on drilling rigs, especially thoseon offshore platforms. There has thus been generally a trade-off betweencapacity, longevity, repairability and resistance to blinding of thescreens.

There is a need for a supported (either non-flat or flat) screen whichis consumable, efficient and cost-effective, yet readily andinexpensively made, easy to handle, and relatively inexpensive totransport.

SUMMARY OF THE PRESENT INVENTION

The present invention discloses, in certain embodiments, a screen forvibrating screen apparatus. The screen has one or more upper layers ofscreen, screen cloth, and/or mesh. If more than one layer is used, theymay be bonded together at discrete points, at discrete areas, or overtheir entire surface. The layer or layers are mounted on frame apparatuswhich may include a solid side support on each of two spaced apart sidesof the layer(s), or may include a full four sided screen frame. A stripor strips of support material (e.g. flat steel, aluminum or plasticstrips--of any width, but in certain preferred embodiments rangingbetween a half inch to three inches in width; and of any thickness, butin certain preferred embodiments ranging between one-thirty second andone-eighth inches thick, or rods of these materials with a diameterbetween one-thirty second and one-eighth inches; any screen may usestrips made from different materials, e.g. cross-strips of plastic andend strips of steel, or vice versa) are secured across two or more framesides. With respect to a two sided frame wherein the two sides areparallel and spaced apart, a strip or strips may be, according to thisinvention, disposed parallel to the two sides; and, if more than onestrip is used, spaced apart across the area of the layer or layers. Itis also within the scope of this invention to use a strip or stripswhich are disposed in a manner non-parallel to the two sides. In oneaspect such non-parallel strips may extend diagonally from one end ofone side of the frame, across the layer or layers, to a diagonallyopposite end of the other side. In another aspect such a strip mayextend from any point of a frame side to any point on a non-framed sideof the layer or layers. Any such strip (or rod) may be bonded, sintered,welded or otherwise secured (herein referred to collectively as"bonded") at any point to the layer or layers; at substantially everypoint of contact between the strip(s) and the layer(s); or at selectedintermediate contact points.

In certain embodiments a screen assembly for a vibratory separator isprovided that has a corrugated support plate having a plurality ofalternating raised portions and lower portions, the corrugated supportplate having a plurality of spaced apart openings therethrough, a screenframe with a first pair of spaced apart first sides and a second pair ofspaced apart second sides, the first sides spaced apart by the secondsides and connected thereto, the frame having a plurality of spacedapart support strips extending beneath the corrugated support plate,each support strip independent of and not connected to the other supportstrips along its length, each support strip having two spaced apart endseach connected to a spaced apart side of the frame and to which thecorrugated support plate is secured. Such a screen assembly may,optionally, have at least one projecting portion on each support stripfor reception within a raised portion of the corrugated support plate,and screening material on the corrugated support plate.

In certain embodiments such a strip (or strips) is used with anundulating three-dimensional layer or layers of screen, screen cloth,screen mesh, or some combination thereof (either non-bonded layers orbonded layers if multiple layers are present). If the undulatinglayer(s) present certain downwardly projecting areas, e.g. troughsbetween valleys, some or all of the troughs may, within the scope ofthis invention, be bonded to the strip(s) or portions thereof, and allor only a portion of a trough may be bonded to the strip(s).

Certain prior art shaker screens have a frame side with an in-turnededge which facilitates hooking of the screen, e.g. to a vibratingbasket. In one embodiment of the present invention a strip as describedabove extending between two frame sides also extends into and becomesthis in-turned hooked edge. In another aspect a strip is secured to aportion of a hook. To inhibit or prevent fluid leakage at the hook/stripinterface, a steel strip may be welded to a metal hook (or a non-metalstrip may be bonded to a metal or non-metal hook). In one aspect typicalframe sides are not used and only a series of strips with hook edgessupport the screening material and provide for its mounting to a shaleshaker.

In other embodiments in which two frame sides are used, support stripsat opposite ends of the frame sides may also serve as end members acrossthe layer(s) ends which do not have frame sides. In one aspect suchstrips are emplaced at the leading and trailing edges of the layers.

In embodiments of this invention in which the layer (or layers) arenon-flat (e.g. undulating) and there is some sort of extended depressedor lower areas on or across the layers which provide a generally lowerpath for fluid moving on part of or all the way across a screen, thestrip or strips according to this invention may be placed beneath thelayer or layers at any desired angle to the direction of flow of thefluid across the screen. Also, in those cases in which the entire screensurface has undulations in a same general direction, the screen may bedisposed so that fluid flows across the screen either generally in thesame direction as the undulations or transverse to such a direction. Ineither case, a strip or strips beneath the layer(s) may be in thedirection of flow or transverse to it.

In one aspect the strips (or rods) described above have one or moreprojecting portions formed integrally thereof or secured thereto whichproject into troughs or areas of the layer(s). Such projecting portionsmay be shaped and configured to mate with the shape of a hill, valley,trough or indented area; may be bonded to the layer(s) at such areas;may be bonded only to the sides of such areas and not to the uppermostportion of a top portion thereof; or may be adjacent such areas withoutbonding thereto. If there is a series of parallel troughs or a pluralityof adjacent indented areas, such projections may be provided in all suchtroughs or areas; in only on such trough or area; in troughs or areasonly adjacent frame sides; or in only middle troughs or areas. It iswithin the scope of this invention in embodiments in which the screenhas a series of parallel troughs, to use alternating flat strips andstrips with one or more projections as described above. It is alsowithin the scope of this invention to use non-flat strips which have ashape that corresponds to the series of troughs, e.g. with undulatinglayer(s), a corresponding undulating strip is used. Such strips may beused instead of or in combination with flat strips as previouslydescribed. Any strip herein may have holes through it to facilitatefluid flow. In one aspect any strip, combination of strips, or patternof strips disclosed herein may be used with a generally flat("two-dimensional") screen. In any screen disclosed herein the screeningmaterial may be sintered to itself, individual screen wires may besintered to each other, one or more layers of screen material, cloth,mesh, or screen may be sintered to each other; and any screen materialmay be sintered to any strip disclosed herein, either entirely along itslength or at selected points or areas therealong.

The present invention, in one embodiment includes a shale shaker with aframe; a "basket" or screen mounting apparatus; one or more screens asdescribed above and below; and basket vibrating apparatus.

It is within the scope of this invention to provide a screen asdisclosed in U.S. Pat. Nos. 5,417,793; 5,417 858; and 5,417,859, but todelete the apertured plate required by these patents and to use insteada coarse mesh or a coarse flexible mesh. In certain preferredembodiments this mesh ranges in size between a 1 mesh to a 3 mesh, witha 2 mesh used in one particular embodiment. It is within the scope ofthis invention to use any strip, combination of strips, or pattern ofstrips in place of the apertured plate required by the three listedpatents. It is within the scope of this invention to use any strip orstrips disclosed herein in combination with the apertured plate requiredby the three listed patents.

The invention, in certain embodiments, discloses a screen for avibrating separator or shaker that has increased capacity without anincrease in overall dimensions. It furthermore accommodates desirableattributes such as resistance to blinding, repairability and longevity.The screen, substantially horizontal when placed on a separator foroperation, is formed from one or more layers of mesh. The one or morelayers of mesh are formed into an alternating series of ridges andchannels lying substantially within the plane of the screen. The ridgesincrease the surface area of the screen without increasing the overalldimensions of the screen, thus improving flow capacity. Additionally,particles tend to drop into the channels, leaving the tops of the ridgesexposed to fluids for relatively unimpeded flow through the screen thatfurther improves flow rates. Furthermore, the ridges and channels tendto assist in evenly distributing separated particles across the screen.Uneven distribution, due to for example rolling of the screen from sideto side when used on offshore platforms, degrades flow capacity of thescreen.

In accordance with another aspect of the invention, the wire mesh isbonded to a rigid or semi-rigid panel having an array of openings thatare very large as compared to those of the mesh. The support panel isformed with or bent into a series of alternating ridges and channels tocreate the ridges and channels in the wire mesh when it is bonded to thepanel. The openings in the panel create, in effect, a plurality ofindividual screen cells when the wire mesh is bonded to the panel aroundeach opening. When a portion of wire mesh fails or is torn within acell, the screen is repaired by cutting the remaining mesh from the cellopening and plugging the cell opening with a solid piece of material.

In accordance with another aspect of the invention, the ridges andchannels of the panel have substantially flat surfaces on which theopenings are located. A substantially planar opening allows a flat plugto be inserted into the opening for improved fit and sealing. The plugis preferably formed with an edge that facilitates insertion intoopening and into which the edge of the cell opening snugly fits, makinga repair quick and easy.

In accordance with another aspect of the invention, the ridges have agenerally triangular cross section. In a preferred embodiment, theridges are formed from two surfaces in a triangular configuration andthe channel is formed from a flat bottom surface extending between theridges. This geometry tends to maximize effective or useful surface areaof the screen, especially if flat surfaces are used on the ridge tofacilitate repair. During normal operation of the separator or shaker,most of the particles fall into the channel and the material to beseparated tends to flow through the screen along the sides of the ridgesand the bottom of the channel. A generally triangular configuration ofthe ridge tends to expose greater screen area to the flow and tominimize the amount of area on top of the ridge that tends not to beexposed to material flow.

In another aspect a screen according to the present invention has alower perforated corrugated plate with a plurality of triangularapertures or openings forming the perforations through the plate. In oneaspect the triangles are congruent, of similar size, and are arrayedside-to-side across the plate. In certain aspects when a corrugatedplate is used, no plastic grid is placed or used between screens ormeshes or between a plate and screening material. The mesh, meshes,screen, screens, or screening material(s) are secured on the platedirectly with the use of adhesive on the plate, e.g. but not limited topowder adhesive, without the use of a plastic or adhesive grid.Alternatively such a grid may be used. In certain aspects in which acorrugated perforated plate is used, the screen, e mesh or screeningmaterial does not contact a strip or multiple strips disposed beneaththe plate. In one aspect a corrugated perforated plate is secured to aframe comprised of sides. In another aspect strips as described hereinare used with such a frame for certain embodiments. In such a devicescreening material or mesh secured to the corrugated perforated platedoes not contact or bond to the strip/frame assembly.

It is, therefore, an object of at least certain preferred embodiments ofthe present invention to provide:

New, useful, unique, efficient, non-obvious screens, filtering screens,two- or three-dimensional screens; flat or non-flat screens; mountingsfor them; such screens with one or more bottom support strips or rods;such screens in which screening material is on a corrugated perforatedplate which itself is on strip(s) and/or on a frame; and shale shakerswith such items;

Such screens which overcome the problems, limitations and disadvantagesof screens with lower apertured plates;

Such a screen with a corrugated perforated solid support plate;

Such a plate with triangular shaped perforations;

Such a screen for a shale shaker with one or more bottom support strips;such a screen also with one or more strip or rod projections forprojecting above a bottom strip or apertured plate into an indentationor raised part in an upper screen layer or layers; and

A shale shaker with one or more such screens.

Certain embodiments of this invention are not limited to any particularindividual feature disclosed here, but include combinations of themdistinguished from the prior art with their structures and functions.Features of the invention have been broadly described so that thedetailed descriptions that follow may be better understood, and in orderthat the contributions of this invention to the arts may be betterappreciated. There are, of course, additional aspects of the inventiondescribed below and which may be included in the subject matter of theclaims to this invention. Those skilled in the art who have the benefitof this invention, its teachings, and suggestions will appreciate thatthe conceptions of this disclosure may be used as a basis or creativeimpetus for designing other structures, methods and systems for carryingout and practicing the present invention. The claims of this inventionshould be read to include any legally equivalent devices or methodswhich do not depart from the spirit and scope of the present invention.

The present invention recognizes and addresses the previously-mentionedproblems and long-felt needs and provides a solution to those problemsand a satisfactory meeting of those needs in its various possibleembodiments and equivalents thereof. To one of skill in this art who hasthe benefits of this invention's realizations, teachings, disclosures,and suggestions, other purposes and advantages will be appreciated fromthe following description of preferred embodiments, given for thepurpose of disclosure, when taken in conjunction with the accompanyingdrawings. The detail in these descriptions is not intended to thwartthis patent's object to claim this invention no matter how others maylater disguise it by variations in form or additions of furtherimprovements.

DESCRIPTION OF THE DRAWINGS

A more particular description of embodiments of the invention brieflysummarized above may be had by references to the embodiments which areshown in the drawings which form a part of this specification. Thesedrawings illustrate certain preferred embodiments and are not to be usedto improperly limit the scope of the invention which may have otherequally effective or equivalent embodiments.

FIG. 1A is a perspective view of a screen according to the presentinvention.

FIG. 1B is a side view of the screen of FIG. 1A.

FIG. 1C is an end view of the screen of FIG. 1A.

FIG. 1D is a bottom view of the screen of FIG. 1A.

FIG. 2A is a top view of a screen according to the present invention.

FIG. 2B is a side view of the screen of FIG. 2A.

FIG. 2C is a bottom view of the screen of FIG. 2A.

FIG. 3 is a bottom view of a screen according to the present invention.

FIG. 4 is a bottom view of a screen according to the present invention.

FIG. 5 is an bottom view of a screen according to the present invention.

FIG. 6 is a bottom view of a screen according to the present invention.

FIG. 7A is a top view of a screen according to the present invention.

FIG. 7B is a bottom view of the screen of FIG. 7A.

FIG. 7C is an end view of the screen of FIG. 7A.

FIG. 7D is a side view of the screen of FIG. 7A.

FIG. 8A is a bottom view of part of a screen with cross strips accordingto the present invention.

FIG. 8B is an end view of part of the screen of FIG. 8A.

FIG. 8C is an end view of part of the screen of FIG. 8B.

FIG. 9 is an end cross-sectional view of a strip for use in the presentinvention.

FIG. 10 is an end cross-sectional view of a strip for use in the presentinvention.

FIG. 11 is an end cross-sectional view of a strip for use in the presentinvention.

FIG. 12 is an end view of a screen according to the present invention.

FIG. 13 is an end view of a screen according to the present invention.

FIG. 14 is a perspective view of a shale shaker according to the presentinvention.

FIG. 15A is a bottom view of a screen according to the presentinvention.

FIG. 15B is a side view of the screen of FIG. 15A.

FIG. 16A is a top view of a support strip according to the presentinvention.

FIG. 16B is a side view of the support strip of FIG. 16A.

FIG. 17A is a top view of a support strip according to the presentinvention.

FIG. 17B is a side view of the support strip of FIG. 17A.

FIG. 18 is a side view of a screen according to the present invention.

FIG. 19 is a perspective view of a screen according to the presentinvention.

FIG. 20 is a side view of the screen of the FIG. 19.

FIG. 21 is a side view opposite the side of FIG. 20 of the screen ofFIG. 1.

FIG. 22 is an end view of the screen of FIG. 19.

FIG. 23 is an end view of an end opposite the end of FIG. 22 of thescreen of FIG. 19.

FIG. 24 is a top view of the screen of FIG. 19.

FIG. 25 is a bottom view of a screen according to the present invention.

FIG. 26 is a perspective view of a screen according to the presentinvention.

FIG. 27 is a top view of the screen of FIG. 26.

FIG. 28 is a bottom view of the screen of FIG. 26.

FIG. 29 is a side view of one side of the screen of FIG. 26.

FIG. 30 is a side view of another side of the screen of FIG. 26 oppositethe side shown in FIG. 29.

FIG. 31 is an end view of the screen of FIG. 26.

FIG. 32 is another end view of the screen of FIG. 26 opposite the endshown in FIG. 31.

FIG. 33 is a perspective view of a screen according to the presentinvention.

FIG. 34 is a top view of the screen of FIG. 33.

FIG. 35 is a side view of one side of the screen of FIG. 33.

FIG. 36 is a side view of another side of the screen of FIG. 33.

FIG. 37 is an end view of the screen of FIG. 33.

FIG. 38 is another end view of the screen of FIG. 33 opposite the endshown in FIG. 37.

FIG. 39 is an end view of a screen according to the present invention.

FIG. 40 is a plan view of the screen of FIG. 39.

FIG. 41 is a plan view of an alternate embodiment of a screen accordingto the present invention.

FIG. 42 is an end view of the screen of FIG. 41.

FIG. 43 is a perspective view of a portion of a screen like that ofFIGS. 41 and 42.

FIG. 44 is a top plan view of a plug for repairing the screen of FIG.43.

FIG. 45 is a cross-section of the plug of FIG. 44, taken a long sectionline 45--45.

FIG. 46 is an end view of a portion of an end view screen like that ofFIG. 43 mounted to basket of a shaker, showing a latching mechanism forsecuring the screen to the shaker.

FIG. 47 is an end view of the screen illustrated in FIG. 39.

FIGS. 48 and 49 are end views of screens.

FIG. 50 is an end view of a plug according to this invention.

FIG. 51A is a top view of a screen frame according to the presentinvention.

FIG. 51B is an enlargement of a portion of FIG. 51A.

FIG. 51C is an end view of a strip of the screen frame of FIG. 51A.

FIG. 52 is an alternative strip interlocking structure for a screenframe as in FIG. 51A.

FIG. 53 is an alternative strip interlocking structure for a screenframe as in FIG. 51A.

FIGS. 54 and 55 are top views of a portion of a plate.

FIG. 56 is a perspective view of a screen according to the presentinvention.

FIG. 57 is an enlarged portion of part of the screen of FIG. 56.

FIGS. 58-59, 60, 61, 62 present end views of corrugated perforatedplates according to the present invention which structure may also beused for strips according to the present invention.

DESCRIPTION OF EMBODIMENTS PREFERRED AT THE TIME OF FILING FOR THISPATENT

FIG. 1A shows a screen 10 according to the present invention with aframe with two sides 12 and 14 with strips 20 extending between the twosides 12 and 14; and screen material 16 on the strips 20 and connectedto the sides 12 and 14. Screen material 16 (and any other screen orscreening material disclosed herein) represents any known mesh, screen,or screens, used in any combination, bonded together or unbonded. Thescreen material 16 as shown is "three-dimensional," i.e., not generallyflat and has undulating portions with hills 22 (as seen in FIGS. 1A-1C)and valleys 24. (It is within the scope of this invention for thescreening material 16 and any other screening material herein to begenerally flat.)

Plugs 26 may plug ends of the hills 22. Incorporated fully herein byreference is the disclosure of co-owned pending U.S. application Ser.No. 08/282,983 filed on Jul. 29, 1994 entitled "Shale Shaker Screens"which discloses three-dimensional screens with plugged ends.

In the screen 10 each bottom part 28 of a valley 24 is glued withadhesive, e.g. but not limited to epoxy, to the cross strips 20 wherethe strips 20 run under the screen material 16. The frame sides 12 and14 have, optionally, a hook portion 30 which facilitates screen mountingin certain shale shakers.

As shown in FIG. 1A the valleys 24 and hills 22 run generally parallelto the frame sides 12 and 14 and, when the screen 10 is mounted in ashale shaker, the direction of flow of drilling fluid (indicated by thearrow labelled "FLOW") is generally the same as the direction in whichthe valleys 24 and the hills 22 run.

FIG. 2A shows a screen 30 according to the present invention which asframe sides 32 and 34 between which is mounted undulating screenmaterial 31. Any strip or strip combination disclosed herein may be usedon the screen 30 below the screen material 31. The screen material 31has hilltops 36 and valleys 38 which are generally perpendicular to theframe sides 32 and 34 and run across the screen 30 from one side 32 tothe other side 34. When mounted on a shale shaker the direction of flowof drilling fluid across the screen 30 (as shown by the arrow labelled"FLOW") is at right angles to the general direction of the hills andvalley. In one embodiment the strips are aligned with the direction ofthe valleys and, in another embodiment, there is a strip or rod undereach valley. Instead of a strip or strips beneath the screen material31, an apertured plate (which is not an equivalent of a rod or strip orof a series of strips) may be used.

FIGS. 3-6 show alternative configurations of bottom support stripcombinations which may be used with any screen disclosed herein. Thescreening material may be any embodiment as disclosed herein. FIG. 3shows an embodiment of a screen 40 with screening material 41 betweenframe sides 46 and 47 and a bottom support structure with cross strips42 (like the previously described strips) and end strips 44 and 45(which are like previously described strips but are at ends of thescreening material 41).

FIG. 4 shows a screen 50 according to the present invention withscreening material 51 between frame sides 52, 53, 54, and 55 and crossstrips 56.

FIG. 5 illustrates a screen 60 with screening material 61 between framesides 62 and 63 with end strips 64 and 65 and diagonal cross strips 66.It is within the scope of this invention to use strips that are not fulldiagonals, but extend from any point on a first frame side to any pointon a second frame side or strip which second frame side or strip is at aright angle to the first frame side.

FIG. 6 illustrates a screen 70 with screening material 71 between framesides 72 and 73 with cross strips 74, cross strips 75 and end strips 76.

FIG. 7A shows a screen 80 with frame sides 82 and 83 between which issecured screening material 81. The frame sides include hooks 84. Abottom support 85 is a rigid metal sheet with a plurality of openingstherethrough. The screening material 81 is undulating with hilltops 86and valleys 87. The screen 80 is emplaced in a shale shaker so that thedirection of flow of drilling fluid across the screen (as shown by arrowlabelled "FLOW") transverse to the general direction of the hills andvalleys. A support strip or strips as disclosed herein may be used withthis screen.

An opening 88 at the end of each undulating section of the screeningmaterial 81 may be closed off by initially applying an excess ofscreening material 81 so that a portion thereof extends beyond what willbe the final outer boundary of the screening material. The excessportion is cut, folded back over the opening to close it off, and thensecured in place with adhesive or welding.

FIG. 8A shows a bottom strip support assembly 90 for a screen accordingto the present invention. A plurality of strips 91 extend between andare secured to frame sides 92 and 93. as shown in FIG. 8B, a strip 91 iswelded along a line 94 to a part of a screen hook 95. The weld is sizedand configured to prevent leakage at the hook/strip interface. A sleeve96 made of galvanized metal encases the hook for added strength andprotection.

In certain embodiments of a screen as in FIG. 8A, the strips 91 arebetween one-thirty second and one-eighth inches thick and aboutforty-five and a half inches long; the frame sides 92, 93 are aboutthirty six inches long; the strips 91 are made from galvanized steel;the frame sides 92, 93 are made from 20 gauge galvanized steel; and thesleeve 96 is made from galvanized steel.

FIG. 9 illustrates a screen support strip 100 with hilltops 101 andvalleys 102 for corresponding to similar hills and valleys in a screenor screening material to which the strip is applied.

FIG. 10 illustrates a screen support strip 110 according to the presentinvention which has a bottom flat strip 111 and an undulating strip 112fixed to the bottom flat strip 111. The undulating strip 112 hashilltops 113 and valleys 114 for corresponding to a screen or screeningmaterial with similar hills and valleys.

FIG. 11 illustrates a screen support strip 120 like the screen supportstrip 110, but with fewer projecting portions 125 so that when a screenwith multiple troughs or indentations is supported by the strip 120,only every other trough or indentation in the screen (or screeningmaterial) will have a projecting portion 125 therein. It is within thescope of this invention to select any particular trough, plurality oftroughs, or pattern of troughs or indentations to have a projectionsupport portion therein. The screen support 120 has a lower strip 121and the upper projecting portions 125, which may also be strips.

FIG. 12 illustrates a screen 130 according to the present invention withscreening material 131 (which may be any screen or screening materialdisclosed herein) supported by a support strip 132. The support strip132 has a bottom strip 133 and an undulating strip 134 secured thereto.The screening material 131 may rest on the undulating strip 134 or someor all of the undulating strip 134 may be bonded to the screeningmaterial.

FIG. 13 illustrates a screen 140 according to the present inventionwhich has screening material 141 (which may be any screen or screeningmaterial disclosed herein) supported by a support strip 142. The supportstrip 142 has a lower strip 143 and projecting strip portions 144secured to the lower strip 143. The projecting strip portions 144project up into hills formed in the screening material 141. In anyembodiment of this invention in which part of a support strip projectsup into a raised part of a screen, the projecting strip may be connectedto, adhesively bonded to, or welded to the screen at any selected point,line, points, or lines in the raised screen part. As shown in FIG. 13,the projecting strip portions are not bonded to, connected to or weldedto the tops 145 of screening material 141; nor are they bonded to,welded to, or connected to lower portions 146 of the raised parts of thescreening material 141. Alternatively the projecting strip portions 144may be bonded to, connected to, or welded to only the tops 145 of theraised parts of the screening material; and/or to the lower portions146.

Referring now to FIG. 14, a shale shaker 210 according to the presentinvention has a screen 220 (with screen or screening cloth or mesh asdesired) according to the present invention mounted on vibratable screenmounting apparatus or "basket" 212. The screen 220 may be any screendisclosed herein or have nay combination of any feature or features ofany screen or screen part disclosed herein; and any such screen may beused with any appropriate shaker or screening apparatus. The basket 212is mounted on springs 214 (only two shown; two as shown are on theopposite side) which are supported from a frame 216. The basket 212 isvibrated by a motor 202 and interconnected vibrating apparatus 218 whichis mounted on the basket 212 for vibrating the basket and the screens.Elevator apparatus 208 provides for raising and lowering of the basketend. The screen 220 may be any screen disclosed herein.

FIG. 15A shows a screen 250 like the screen in FIG. 1D, but without anyframe sides. The screen 250 has a plurality of bottom support strips252, each of which has two upper in-turned edges formed into a mountinghook 254. Undulating screening material 256 is bonded to the strips 252.

FIG. 16A shows a support strip 260 according to the present invention,with an upper projecting strip 264 secured to a lower strip 262. Theupper projecting strip 264 is narrower in width than the lower strip262. Any of the previously described strips with a projecting upperstrip and a lower strip may have an upper strip that is narrower inwidth than the lower strip.

FIG. 17A discloses a support strip 270 with a lower strip 272 and anupper strip 274 secured to the lower strip 272. A series of openings 276is provided through the lower strip 272 to facilitate fluid flow. Aseries of openings 278 is provided through the upper strip 274. Anystrip or rod disclosed herein may have, in certain embodiments, holestherethrough to promote fluid flow. Any strip or rod disclosed hereinwith an upper projecting portion and a lower strip or rod may have holesin the upper strip or rod, the lower strip or rod, or both to promotefluid flow.

FIG. 18 discloses an improvement to screens with upper screeningmaterial and a lower rigid perforated metal sheet or apertured plate,including but not limited to improvements for screens as disclosed inU.S. Pat. Nos. 5,417,793; 5,417,858; and 5,417,859. A screen 280 withscreening material 281 has a lower apertured plate 282 (as disclosed,e.g., in the three listed patents). Upper projecting strips 284 aresecured to the lower apertured plate 282. The upper projecting strips284 may or may not be bonded to the screening material 281 and may ormay not have holes therethrough. The screening material may be bonded toitself, and/or to any apertured plate, strip, or rod. Any upperprojecting rod, strip, combination of strips or rods, or pattern ofstrips or rods disclosed herein may be used with screens with a lowerapertured plate, including but not limited to those disclosed in thethree listed patents.

FIGS. 19-38 present various screen designs according to the presentinvention and various views thereof.

In the following description, like numbers refer to like parts.Referring to FIGS. 39, 40, and 47 vibrating screen 700 includes a firstlayer 702 of wire mesh web and a second layer 704 of wire mesh web.Preferably, the first mesh layer is made from a web of bolting clothgrade wire mesh. The second mesh layer is a backing mesh. The first andthe second mesh layers are supported on frame 706. The frame is formedto create a plurality of ridges 708 running the length of the screen700, defining therebetween a plurality of channels 710. Channels run thelength of the screen 700 from the back end of the screen to its frontend 712. Attached to each side of the screen are hook straps 714. Eachhook strap is bonded to the frame 708 and mesh layers 702. Steel straps716 laterally tension the first and second mesh layers to maintain inthe surface of the screen the channels and ridges.

The screen is secured to a shaker in a well known manner by hookingaround the hookstraps and tightening rails disposed along the edges ofthe basket of a shaker (not shown). A series of stringers below thescreen (not shown) cause the screen to bow as the rails pivot downwardlyas they are tightened.

During operation, material containing solids to be separated is pouredonto the back of the screen. Solids tend to collect in the channels andmove toward the front end of the screen when the screen is vibrated.Fluid and particles smaller than the openings in the layer of mesh flowthrough the mesh along the sides of ridges 708 and the bottoms ofchannels 710.

Referring now to FIGS. 41 and 42, in an alternate embodiment of screen100, a first layer of wire mesh 402, a second layer of wire mesh 404 anda third layer of wire mesh 405 (the wire meshes are shown only in FIG.42 exploded away from panel 302) are bonded to panel 302 to form screen400. The first and second layers are a bolting cloth grade wire mesh.The third layer 405 is a mill grade or market grade wire mesh supportingthe first and second layers. The panel is formed from a sheet of metalby punching or cutting an array of elongated, rectangular openings 304into the sheet of metal according to a predetermined pattern. Theopenings have uniform size and shape. The sheet is then bent with apress or rolled into a corrugated configuration substantially as shownin FIG. 42. The corrugated configuration is comprised of alternatingseries of triangular shaped ridges 306 and flat bottom channels 308.Each triangular ridge 308 has two substantially flat side surfacesseparated by a narrow peak 309.

Along each end of the panel is bonded a frame 310. Frame 310 iscontoured to fit and provide support for the ridges 306. The screen isformed so that its side edges run along the peak of a ridge 306.Terminating the sides of the screen along a ridge helps to preventmaterial from falling between the screen and the inside wall of a shakerbasket (not shown) over which the screen is placed.

Although other ridge geometries having flat surfaces may be used, thetriangular configuration of the ridges and the flat bottom of thechannels tend to maximize effective flat surface area for placement ofthe openings 304. Each opening 304 is located on a flat surface ofeither a side of a ridge or a bottom surface of a channel. Therectangular shape of the openings allow as much of the flat surface tobe cut with openings allow as much of the flat surface to be cut withopenings as is possible while leaving enough solid area to remain toform a grid or lattice-like structure that will retain its shape and notbreak during normal use.

Once the panel is formed, the first layer 402, the second layer 404 andthird layer 405 of wire mesh are heated and then bonded to the panel.The heating expands the wire mesh. After the wire mesh is bonded to thepanel, it cools and contracts, thus tensioning the wire mesh. Tensioninghelps to maintain uniformity of the wire mesh and to keep the first andsecond layers of wire mesh together during operation, thus giving thescreen a finer cutting point. Tensioning the wire mesh also assists inconveying particles to the end of the screen. A slack screen will notconvey particles as well, especially when heavily loaded.

Referring now to FIG. 43, a perspective view of a portion of a screen400 shows a layer of wire mesh 562, which includes wire mesh webs 402,404 and 405 (FIG. 42) bonded to panel 302. Should a tear develop in wiremesh layer 562, the wire mesh surrounding the tear is cut from aroundthe opening 304 in which the tear occurs. A plug 564 is then insertedinto the opening in the screen to seal the screen.

Referring now to FIG. 44 and 45, plug 564 is made of an elastic rubberor similar elastomeric material. Its width and length are very slightlylarger than one of the openings 304. It has a flat top sectionsurrounded on all sides by a skirt-like side edge 602. The side edge isadapted for enabling the plug to be manually inserted into one of theopenings 304 and to seal securely against the side of the opening. Theside edges have an outwardly tapering bottom section 604 and a channel606. The tapering bottom section is sufficiently flexible enough todeflect inwardly under force of the edges of the opening when the plugis pushed into the opening. Deflection of the bottom of the sides pullsinwardly a lower edge of channel 606, thereby providing sufficientclearance to push the plug further down into an opening 304 to the pointthe upper edge of the channel engages the upper edge of the opening. Thewidth of channel 606 is slightly larger than the thickness of the edgeof an opening 304 (which includes the thickness of the panel and twolayers of wire mesh). Therefore, the bottom tapering section 604 springsback, locking the plug into place and sealing it against the edges ofthe opening. Support ribs 608 provide lateral strength to the plug sothat it does not deflect downward when loaded during operation, in amanner that would pull the top edge of the channel away from the edge ofthe opening and allow the load to force the plug through the bottom ofthe opening.

Referring to FIG. 46, the screen 400 is secured to a basket of a shaker(not shown) using cam latch 804. Latch 804 is secured to side wall 806of the basket 802. A latching end of latching bar 808 extends through anopening in the wall to engage the top of screen and to force the screenagainst bracket 810. Handle 812 pivots about pin 814. U-bolt 816 isconnected through rod 818. Rod 818 extends through handle 812. The otherend of the U-bolt (not seen) is connected in a similar fashion to theother end of the rod so that the U-bolt is permitted to swing about rod818 under the handle 812. When handle 812 is pivoted upwardly, thesaddle of the U-bolt lifts up on latching bar 808, causing the latchingbar to pivot about pin 820 and press against the screen. Pulling down onhandle 812 lowers the saddle of U-bolt 816, permitting the latching barto pivot counter-clockwise and release the screen. To assist in quicklyreplacing the screen, slot 822 allows pin 820 to be moved back and thusallows the latching member 808 to be pulled behind the side of thebasket.

FIG. 48 shows a screen 900 like the screen 700 (FIGS. 39, 40) with asimilar length and width (see FIG. 40), but with a somewhat differentscreen shape as viewed from the end (e.g. as in FIG. 39). The screen 900has a first layer of wire mesh 902 and a second layer of wire mesh web904 (shown apart from the frame prior to final assembly after which themeshes are on the frame. It is within the scope of this invention to useonly one screening layer for any screen described herein or to use threeor more layers. A frame 906 (like the frame of the screen 700) supportsthe mesh and/or screening layers. In one aspect the layers shown for thescreen rest one on top of the other and in another aspect one or more orall of the layers are bonded together and in another aspect they arebonded to the frame across their entire surfaces or only around theperiphery thereof. The frame 906 is configured and shaped to correspondto the corrugated shape or undulating shape of the layer(s) above it;alternatively the layer(s) may be made to correspond to the shape of theframe (as viewed on end as in FIG. 39). Ridges 908 have relativelyelongated flat tops as compared to the length of the flat tops of theridges of the screen 700 and flat valleys 912 of the frame 906 arerelatively short as compared to the valleys of the screen 700. It iswithin the scope of this invention for the ridges and valleys to haveany desired width or shape.

FIG. 49 shows a screen 920 like the screens 700 (FIGS. 39, 40) and 900with a similar length and width (see FIG. 2), but with a somewhatdifferent screen shape as viewed from the end. The screen 920 has afirst layer of wire mesh 922, a second layer of wire mesh web 924 and athird layer of mesh or screening 928 (which are on the frame followingfinal fabrication). A frame 926 (like the frame of the screen 900)supports the mesh and/or screening layers. In one aspect the layersshown for the screen rest one on top of the other and in another aspectone or more or all of the layers are bonded together and in anotheraspect they are bonded to the frame across their entire surfaces or onlyaround the periphery thereof. The screens 900 and 920 may be used withor without straps (e.g. as the straps 714 and 716, FIG. 47). Individualcells of the screens 900 and 920 may be shaped as the individual cellsof the screens of FIGS. 40 and 41 or they may be any desired shape,including but not limited to, oval, square, trapezoidal, or triangular(acute, obtuse, isosceles, congruent). The cells of the screens 900 and920 are repairable as are cells of the previously-described screens.

FIG. 50 shows a plug 950 for plugging off a cell of a screen accordingto the present invention. The plug 950 has a body member 952 and ears956 which project from legs 954 depending from the body member 952. Theplug 950 is made from a resilient material so the legs 954 are bendableto permit the ears 956 to enter a cell to be repaired and then expandoutwardly so the ears catch and hold on an edge of the cell.

It is within the scope of this invention to have a plug held in a cellby friction fit, any "snap fit" structure, welding or adhesive. A plugaccording may be any desired shape to fit in and mate with the shape ofa cell. The plug may be solid or it may be solid with openings, holes orperforations therethrough. In one aspect in which a cell is notinitially behind a torn screen area a cell or cells is placed at thetorn area on one side of the screen and a plug is inserted into the cellfrom the other side of the screen to repair a torn area.

FIG. 51A shows a screen frame 500 according to the present inventionwith a plurality of spaced-apart strips 502 (made of any suitable metalor metal-like material) secured to and between spaced-apart sides 504.Each end 506 of each strip 502 is received and held in a recess 524 in aside 504. The recess 524 corresponds in shape to the shape of the end506 and a shoulder 526 of each strip 502 abuts a side 504. The end 506may be inserted into the recess 524 from the side (to the left in FIG.51B) or from above or below. The top and bottom strips 502 (as viewed inFIG. 51A) each has two humps or ridges 553 (see FIG. 51C) which arelocated, sized, and configured to be received in correspondingcorrugations of a corrugated plate and/or corrugated screen assembly. itis within the scope of this invention for each strip to have one, two,or a plurality of multiple humps or ridges. In one aspect there is onehump or ridge for each corrugation on a superimposed plate and/or screenassembly.

FIG. 52 (prior art) shows a strip interlocking structure which includesa bulb 505 at each end of a strip 503 (disposed in a frame as are thestrips 502). The bulb 505 is in a recess 525 in a side 501 (like thesides 504). The bulb 505 is lifted out from the recess 525 for removalor inserted into it from below or above for installation. A frame withsuch strips is prior art.

FIG. 53 (prior art) shows a strip interlocking structure which includesa bulb 509 at each end of a strip 508 (disposed in a frame as are thestrips 502). The bulb 509 is in a recess 530 in a side 507 (like thesides 504). The bulb 509 is lifted out from the recess 530 for removalor inserted into it from below or above for installation. An enlargedend 531 resides removably in a recess 532 and prevents the strip 508from inadvertently moving out from the recess 530 to the side (to theleft in FIG. 53). A frame with such strips is prior art.

FIG. 54 shows a pattern of triangular openings for a perforated plate510 (made of metal or metal-like material) (shown partially) accordingto the present invention usable with any embodiment disclosed herein ofa perforated plate or that employs a perforated plate. The openings 511are positioned side-by-side in an array that extends acrosssubstantially all of a plate. The plate may be corrugated or flat or acombination thereof with alternating flat and corrugated portions.

FIG. 55 shows a typical pattern of triangular openings for a perforatedplate 510 according to the present invention usable with any embodimentdisclosed here of a perforated plate or that employs a perforated plate.Openings 513 are positioned side-by-side in an array that extends acrosssubstantially all of a plate. Openings 514 and 515 are spaced apart fromeach other slightly more than the middle openings of the plate 510producing, in certain embodiments, stronger central plate portions 550.The plate may be corrugated or flat or a combination thereof withalternating flat and corrugated portions.

In the pattern of openings as in FIG. 55, the pattern is shiftedslightly as compared to that of the plate 510 to optimize use of ascreening surface. For example, a screen using the pattern in FIG. 54and a web width (distance between two adjacent openings) of 0.125", hasa border of 3/4" on each edge. By shifting the triangle openings to thepattern of FIG. 55, a web width of 0.125" may be maintained whiledecreasing the border. This allows more openings in the screen of FIG.55 as compared to that of FIG. 54, increasing surface area and improvingappearance.

In the pattern of FIG. 54, the openings are arranged in rows with basesand peaks alternating. The peak of one opening is even with the base ofthe next. In the pattern of FIG. 55 the openings 513 are moved closertogether and the peaks of the openings 513 are not even with the base ofthe opening 514 or 515.

FIGS. 56 and 57 show a screen 530 according to the present inventionwith a corrugated support plate 540 (preferably made of metal) having aplurality of triangular openings 538 (not shown in FIG. 56; see FIG. 57)thereacross the surface of and therethrough; optional upturned edges 534and 537 for anchoring the screen 530 to a vibratory shaker; wire mesh ormeshes 539 secured to the plate 540; and plugs 536 at both ends (likepreviously described plugs) to plug ridge openings 532 at each end ofthe corrugations of the plate 540. The plate 540 rests on and is securedto a strip or strips 551 (alternately a frame of multiple stripscriss-crossing the plate 540 or a series all in the same direction, or aperforated plate may be used). In one aspect the strip(s) 551 aredeleted. The strips 551 may be made of any suitable material, including,but not limited to, metal, plastic, fiberglass, rubber, or cermet.

A screen according to the present invention (e.g. as those of FIGS.51A-57) may be made without a plastic grid located between a lower plateand screen(s) or mesh(es) above the plastic grid. When screeningmaterial is bonded to a corrugated perforated plate (e.g. as in FIG.57), thermal expansion puts the screening material in tension. Such aresult is not produced when a plastic grid process is used. A metalcorrugated perforated plate withstands tension induced thereon byscreening material applied and/or bonded thereto. In one aspect theplate is first covered with adhesive (e.g. powdered epoxy) then themesh(es) and/or screen(s) are palced on the plate. Upon curing of theepoxy, adhesive 541 covers or envelops part of the mesh/screen at thesolid areas of the plate.

FIGS. 58-62 present a variety of configurations for corrugatedperforated plates according to the present invention and/or for stripsaccording to the present invention.

FIG. 58 shows a corrugated plate A on a support strip B having optionalmounting hooks C.

FIG. 59 shows a corrugated plate D on a support strip E. Optionally,mounting hooks may be used with such an assembly.

FIG. 60 shows a support strip F. A corrugated perforated plate may havesuch a configuration and mounting hooks may be used with the strips orwith the plate.

FIG. 61 shows a support strip G. A corrugated perforated plate may havesuch a configuration and mounting hooks may be used with the strips orwith the plate.

FIG. 62 shows a corrugated plate H on a support strip I having optionalmounting hooks J.

Any mesh, meshes, screen, screens, screening material(s) or anycombination thereof or any such as described herein may be used with anyof the items shown in FIGS. 58-62.

In conclusion, therefore, it is seen that the present invention and theembodiments disclosed herein and those covered by the appended claimsare well adapted to carry out the objectives and obtain the ends setforth. Certain changes can be made in the subject matter described,shown and claimed without departing from the spirit and the scope ofthis invention. It is realized that changes are possible within thescope of this invention and it is further intended that each element orstep recited in any of the following claims is to be understood asreferring to all equivalent elements or steps. The following claims areintended to cover the invention as broadly as legally possible inwhatever form its principles may be utilized.

What is claimed is:
 1. A screen assembly for a vibratory separator, thescreen assembly comprisinga corrugated support plate having a pluralityof alternating raised portions and lower portions, the corrugatedsupport plate having a plurality of spaced apart openings therethrough,a plurality of spaced apart support strips extending beneath thecorrugated support plate and to which the corrugated support plate issecured, and each support strip having a length and independent of andnot connected to the other support strips along its length, each supportstrip having two spaced apart ends, screening material on the corrugatedsupport plate.
 2. The screen assembly of claim 1 further comprisingaframe to which the corrugated support plate is secured and, wherein eachsupport strip has two spaced apart ends each connected to a spaced apartside of the frame.
 3. The screen assembly of claim 1 whereinthe supportstrips are made of a material from the group consisting of metal,plastic, fiberglass, rubber or cermet.
 4. The screen assembly of claim 1whereinthe spaced-apart openings of the corrugated support plate aretriangular.
 5. The screen assembly of claim 4 wherein the spaced-aparttriangular openings are positioned side-by-side in an array that extendsacross substantially all of the corrugated support plate.
 6. The screenassembly of claim 5 whereinthe array comprises rows of triangularopenings, each row including a repeating pattern of a first, second, andthird triangular opening, the first and third triangular openingspositioned with a main base down and a vertex pointing away from thebase, the second triangular opening positioned between the first andthird triangular openings with a primary vertex pointing toward a lineconnecting the bases of the first and third main triangular openings andpositioned between sides of the first and third triangular openings, thesecond triangular opening with a primary base disposed beyond a linebetween the vertices of the first and third triangular openings thatpoint away from their main bases.
 7. The screen assembly of claim 6whereinthe first triangular openings of adjacent rows are positionedwith their main bases in a side-to-side relationship, the thirdtriangular openings of adjacent rows are positioned with their mainbases in a side-to-side relationship, the second triangular openings ofadjacent rows are positioned with their primary vertices pointing ateach other.
 8. The screen assembly of claim 1 whereinthe corrugatedsupport plate has two spaced-apart opposed sides, each of said sideshaving an upturned edge to facilitate anchoring the screen assembly tothe vibratory separator.
 9. The screen assembly of claim 1 furthercomprisingthe screening material comprising at least one wire meshsecured on the corrugated support plate.
 10. The screen assembly ofclaim 9 whereinthe at least one wire mesh is a plurality of wire meshes.11. The screen assembly of claim 9 further comprisingbonding materialbonding the at least one wire mesh to the corrugated support plate. 12.The screen assembly of claim 11 wherein the bonding material is anadhesive and adhesive envelops solid areas of the corrugated supportplate between the spaced-apart openings of the corrugated support plate.13. The screen assembly of claim 9 wherein the corrugated support plateis made of metal and the at least one wire mesh is bonded directly tothe corrugated support plate with no plastic grid therebetween.
 14. Thescreen assembly of claim 12 wherein the adhesive is cured and the atleast one wire mesh is in tension on the corrugated support plate due tothermal expansion effected during curing of the adhesive.
 15. The screenassembly of claim 1 further comprisinga plug in each opening beneath araised portion.
 16. The screen assembly of claim 1 whereinthe at leastone support strip has at least one projecting portion for receptionwithin a raised portion of the corrugated support plate.
 17. The screenassembly of claim 16 wherein the at least one support strip is aplurality of support strips and the at least one projecting portion isat least two projecting portions, each of the at least two projectingportions projecting into a raised portion of the corrugated supportplate.
 18. The screen assembly of claim 17 wherein for each raisedportion of the corrugated support plate there is a correspondingprojecting portion of each support strip.
 19. A support plate for ascreen assembly for a vibratory shaker, the support plate comprisingabody with a plurality of spaced-apart triangular openings, thespaced-apart triangular openings positioned side-by-side in an arraythat extends across the support plate, and the array comprising rows ofspaced-apart triangular openings, each row including a repeating patternof a first, second, and third triangular opening, the first and thirdtriangular openings positioned with a main base down and a vertexpointing away from the base, the second triangular opening positionedbetween the first and third triangular openings with a primary vertexpointing toward a line connecting the bases of the first and third maintriangular openings and positioned between sides of the first and thirdtriangular openings, the second triangular opening with a primary basedisposed beyond a line between the vertices of the first and thirdtriangular openings that point away from their main bases.
 20. Thesupport plate of claim 19 whereinthe first triangular openings ofadjacent rows are positioned with their main bases in a side-to-siderelationship, the third triangular openings of adjacent rows arepositioned with their main bases in a side-to-side relationship, and thesecond triangular openings of adjacent rows are positioned with theirprimary vertices pointing at each other.